Development of the composite material and coatings based on niobium carbide
Journal Title: Восточно-Европейский журнал передовых технологий - Year 2018, Vol 6, Issue 12
Abstract
<p class="a">We investigated the structure of composites based on the system NbC with a copper bond, obtained by impregnating the porous carbide skeletons with a metallic melt in a vacuum. In order to receive a porous skeleton, the powder of NbC, the average size of ~1 μm, was mixed on a 5 % solution of rubber in gasoline. After drying, the mixture was ground at a sieve into granules, which were pressed into briquettes of dimensions 55×30×10 mm. To ensure the intensification of the process, as well as wetting, impregnation was carried out at a temperature of 1,400 °C. The result was the obtained material with a fine-grained two-phase structure.</p><p class="a">The microstructure was investigated using a method of scanning electron microscopy (SEM), the chemical composition ‒ applying a method for energy dispersion analysis (EDS).</p><p class="a">The hardness was measured by Rockwell (scale C), the fracture toughness ‒ by the indirect Evans-Charles method.</p><p class="a">The composite's structure consists of rounded grains of NbC, which form a continuous skeleton, and the layers of copper bonding. The average size of grains and the intragrain layers of bonding is 1.8 μm and 1.1 µm, respectively.</p><p class="a">An analysis of the interaction zone between NbC and Cu via EDS method revealed the presence of a 0.5 μm thick zone of diffusion, resulting from the redistribution of Nb and Cu by limited solubility. The presence of the diffusion zone makes it possible to provide a solid interphase bonding and, accordingly, the high level of mechanical properties. The hardness and fracture toughness of the obtained material are 40 HRC and 24 MPa×м<sup>1/</sup>2, respectively.</p><p class="a">Given the phase composition and properties of the developed composite, it is recommended to apply it as an alternative for composites of the system WC‒Cu in the form of a monolithic material or coatings. A coating was applied using the method of electric-spark doping, using the manual installation MP-EL2. The coating's thickness is 30 μm, microhardness is ~500 MPa, and the friction coefficient against steel without lubrication is 0.04.</p>The designed materials are recommended for use in friction pairs in the form of a monolithic material, or anti-friction coatings
Authors and Affiliations
Pavlo Prysyazhnyuk, Dmytro Lutsak, Liubomyr Shlapak, Viktor Aulin, Lyubomyr Lutsak, Lubomyr Borushchak, Thaer Abdulwahhab Shihab
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